Mucosal Immunization with a Conserved HIV Envelope Peptide Cocktail Vaccine

描述（由申请人提供）：迫切需要一种安全有效的HIV疫苗，可以在世界大部分地区使用，通过强大的粘膜和全身免疫来预防和/或治疗HIV感染。这项创新拨款提案将测试我们与一种新的霍乱毒素突变体一起开发的高度保守的HIV包膜肽鸡尾酒作为粘膜疫苗接种佐剂的潜力，最好是通过口服途径。先前的研究表明，通过静脉注射弗氏佐剂和/或自体树突状细胞，预防性接种这种肽鸡尾酒可以保护恒河猴免受SHIVku2和SHIV89.6P的慢性感染和艾滋病。我们开发了一种霍乱毒素的双密码子突变体CT2*（专利正在申请中），它作为佐剂有效地用于用HIV肽进行小鼠鼻内免疫，以诱导HIV特异性的粘膜和全身细胞免疫反应。我们还观察到，在用碳酸氢盐中和胃酸后，用CTL表位肽和CT2*口服免疫小鼠，可诱导抗原特异性CTL反应。我们假设高度保守的HIV包膜肽鸡尾酒与CT2*结合将是一种有效的疫苗，通过鼻内和口服给药进行粘膜免疫。为了验证这一假设，我们将首先确认我们开发的霍乱毒素CT2*双密码子突变体在佐剂性方面是否优于另一个已建立的单密码子突变体E112K。在此之后，我们提出在小鼠模型中进行比较分析，通过鼻内和口服途径将肽鸡尾酒与CT2*一起递送，产生抗原特异性细胞免疫反应，将评估对编码HIV包膜蛋白的重组痘苗病毒攻击的保护功效。对于口服免疫，我们还建议测试一种策略，包括将疫苗肽鸡尾酒包封在肠溶胶囊中，当消化道遇到酸时，这种胶囊可以溶解，并将疫苗递送到肠道抗原提呈细胞中（与贝勒医学院的Michael Barry博士合作）。从小鼠研究中选择的最佳粘膜递送策略（鼻内或口服）将用于测试与CT2*佐剂混合的肽鸡尾酒疫苗对恒河猴阴道内致病性SHIV攻击的免疫原性和保护效果。这些研究的成功结果将使我们能够制定肽鸡尾酒粘膜疫苗的临床前开发计划。

DESCRIPTION (provided by applicant): A safe and effective HIV vaccine amicable for use in most parts of the world to prevent and/or treat HIV infection through strong mucosal and systemic immunity is an urgent need. This innovation grant proposal will test the potential of a highly conserved HIV envelope peptide cocktail we developed along with a novel cholera toxin mutant as adjuvant for mucosal vaccination, preferably by the oral route. Previous studies demonstrated that prophylactic vaccination with this peptide cocktail delivered by intravenous route using Freund's adjuvant and/or autologous dendritic cells protected rhesus macaques from chronic infection and AIDS by SHIVku2 and SHIV89.6P. A two-codon mutant of cholera toxin, CT2*, we developed (patent pending), was effective as adjuvant for intranasal immunization of mice with the HIV peptides for inducing HIV-specific mucosal and systemic cellular immune responses. We also observed that oral immunization of mice with a CTL-epitope peptide and CT2*, after neutralizing stomach acid with bicarbonate, resulted in induction of antigen-specific CTL responses. We hypothesize that the highly conserved HIV envelope peptide cocktail when combined with CT2* will be an efficient vaccine for mucosal immunization by intranasal as well as oral delivery. To test this hypothesis, we will first confirm whether the two-codon mutant of cholera toxin CT2* we developed will be superior to another well-established single-codon mutant E112K in terms of adjuvanticity. After this, we propose comparative analysis in the mouse model, for delivery of peptide cocktail along with CT2* by the intranasal and oral routes to generate antigen-specific cellular immune responses that will be assessed for protective efficacy against challenge with recombinant vaccinia virus encoding the HIV envelope protein. For oral immunization, we also propose to test a strategy involving encapsulation of the vaccine peptide cocktail in enteric-coated capsules that are designed to dissolve when encountered with acid in the digestive track and deliver the vaccine to intestinal antigen presenting cells (in collaboration with Dr. Michael Barry, Baylor college of Medicine). The optimal mucosal delivery strategy (intranasal or oral) selected from the mouse studies will be used for testing immunogenicity and protective efficacy of the peptide cocktail vaccine admixed with the CT2* adjuvant in rhesus macaques against intra-vaginal pathogenic SHIV challenge. Successful outcome in these studies should enable us to formulate pre-clinical development plan for mucosal vaccination with the peptide cocktail.